Magneto-transport study of nanocrystalline and polycrystalline manganites La0.75Ca0.25MnO3

We compare structure and magnetic parameters of the polycrystalline and nanocrystalline manganites La 0.75 Ca 0.25 MnO 3 prepared by the carbonate precipitation and the sol–gel methods, respectively. The Curie temperature is surprisingly enhanced for nanocrystalline manganite. An effect of magnetic fields on transport parameters is analyzed for the metallic and semiconducting ranges.